Friction damper
First Claim
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1. A damper ring mountable in a groove defined on a circumferentially inner surface of a rotor of a gas turbine engine to provide a friction damper assembly, the damper ring comprising:
- an outer circumferential surface configured to be centrifugally loaded against a radially inwardly facing surface of the groove; and
a plurality of circumferentially spaced-apart pressure relief dimples defined in the outer circumferential surface of the damper ring, the pressure relief dimples being configured to locally reduce a contact pressure at the outer circumferential surface of the damper ring below a threshold value at which friction forces lock the damper ring against movement in a circumferential direction relative to the rotor, wherein, in use, the pressure relief dimples are deformable into contact with the radially inwardly facing surface of the groove.
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Abstract
A damper ring is mounted in frictional engagement with a radially inwardly facing surface of a circumferential groove defined in a rotary part of a gas turbine engine. Energy dissipation is provided via sliding friction of the ring in the groove. Pressure relief dimples are provided around the outer diameter of the ring for locally reducing contact pressure at the outer diameter below a value at which the damper ring locks in the groove by friction forces when subject to centrifugal loads.
11 Citations
18 Claims
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1. A damper ring mountable in a groove defined on a circumferentially inner surface of a rotor of a gas turbine engine to provide a friction damper assembly, the damper ring comprising:
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an outer circumferential surface configured to be centrifugally loaded against a radially inwardly facing surface of the groove; and a plurality of circumferentially spaced-apart pressure relief dimples defined in the outer circumferential surface of the damper ring, the pressure relief dimples being configured to locally reduce a contact pressure at the outer circumferential surface of the damper ring below a threshold value at which friction forces lock the damper ring against movement in a circumferential direction relative to the rotor, wherein, in use, the pressure relief dimples are deformable into contact with the radially inwardly facing surface of the groove. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A gas turbine engine rotor mounted for rotation about an axis, the rotor comprising:
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a body defining a circumferential groove having a radially inwardly facing surface; and at least one damper ring mounted in the circumferential groove, the at least one damper ring having a plurality of pressure relief dimples formed at spaced intervals in an outer circumferential surface of the at least one damper ring and leaving circumferentially extending lands therebetween, in use, the at least one damper ring being displaceable under a centrifugal load from a first position, in which the lands are in contact with the radially inwardly facing surface of the circumferential groove while the pressure relief dimples are spaced radially inwardly therefrom, to a second position, in which the pressure relief dimples are deformed under the centrifugal load into contact with the radially inwardly facing surface of the circumferential groove. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method of providing frictional damping for a rotor of a gas turbine engine, the rotor having a circumferential groove with a radially inwardly facing surface, the method comprising:
- providing at least one damper ring configured to be centrifugally loaded against the radially inwardly facing surface of the circumferential groove of the rotor when the rotor is rotatably driven; and
adjusting a contact pressure between an outer circumferential surface of the at least one damper ring and the radially inwardly facing surface of the groove below a threshold value at which the at least one damper ring locks against movement in a circumferential direction relative to the rotor when subject to centrifugal loads of a magnitude corresponding to centrifugal loads encountered during engine operation, wherein adjusting comprises providing pressure relief dimples at circumferential intervals in the outer circumferential surface of the at least one damper ring, where the pressure relief dimples are deformed into contact with the radially inwardly facing surface of the groove. - View Dependent Claims (16, 17, 18)
- providing at least one damper ring configured to be centrifugally loaded against the radially inwardly facing surface of the circumferential groove of the rotor when the rotor is rotatably driven; and
Specification